In the case of a wristwatch, electronic modules, for example for storing data, are generally placed inside the watchcase. These electronic modules include an integrated circuit chip connected to a coil acting as antenna for communicating with a read and/or write apparatus via broadcast signals. The read and/or write apparatus can be provided for at least reading the data contained in a memory of the integrated circuit chip or for removing or modifying at least a part of such data and adding further data.
More specifically, the invention relates to a metallic watchcase including a passive type electronic module. The term “passive” means that the module is not provided with its own energy source, such as a battery or an accumulator, to be able to operate. The electric energy of the module is provided by the signals broadcast by the read and/or write apparatus with which it cooperates.
Such watches are provided for example simply for storing an access code for private or protected buildings or ski slopes. Other watches with electronic modules fitted with more complicated integrated circuit chips can contain personal data, such as their owners' medical files.
In some known watches, the electronic module is placed in a hollow, preferably removable bezel, so that the module can be changed if necessary. This solution is not therefore suitable for watches having any type of case. Moreover, if the case includes a bezel or a middle part-bezel, this complicates the manufacture thereof and consequently increases the cost price of the watch.
In other watches, the module is placed in a space provided between the back of the movement of such watches and the back cover or their case, which necessarily increases the volume thereof. Moreover, if the back cover of the case is made of a material that is not non-magnetic, for example steel, the magnetic flux generated or received by the coil of the electronic module experiences significant losses. Even if measures are taken to limit such losses, they are still far from negligible. This reduces the communication distance between a read and/or write apparatus and the electronic module. Finally, even if the back cover of the case is made of a non-magnetic material, for example, plastic material, gold, silver or aluminium, the broadcast signals transmitted and received by the coil of the module which have to pass through the entire thickness of the back cover undergo significant attenuation
It is thus a main object of the invention to overcome the drawbacks of the prior art by providing a watch with a metallic case including an electronic module arranged for attenuating interference due to the metallic watchcase during communication with a data read and/or write apparatus. Further, the watch module is arranged for increasing the read and/or write distance during communication with said apparatus.